1. Field of the Invention
The present invention relates to a novel apparatus and methods for the forming of a building material that may replace more expensive materials or materials that are more limited in supply. The preferred method begins with an extruder with an extrusion die that produces an extruded shell preferably of plastic that may have various profiles but each shell has an open gap preferably formed in its top working surface between spaced and parallel edges of the shell. The shell is then conducted into and through a calibrator where a vacuum is applied to the exterior of the shell to maintain the shape of the shell as it passes through the calibrator. The calibrator has an injection bore that in the preferred embodiment allows the inserting of an injector nozzle of a mixing head injector into and through the injection bore, through a gap in the extruded shell, and into a central shell cavity of the extruded shell as the shell passes through the calibrator. In the preferred embodiment, the mixing head injector mixes and injects a foam core through its injector nozzle and through the injection bore to fill the central shell cavity and the gap downstream from the injector nozzle as the shell passes by the injection bore. The core expands and cures as the shell and core continue through the remainder of the calibrator.
2. Description of Related Art
A number of extrusion devices exist that can aid a person in understanding the art of extrusion and foam filled extrusions. In U.S. Pat. No. 5,783,125 issued to Bastone is disclosed reinforced extrusion products and method of making same. In U.S. Pat. No. 5,393,536 issued to Brandt, a coextrusion apparatus is addressed. These prior devices use a different apparatus for the mixing and injection of a central core and introduce the central core through the extrusion die rather than downstream as done in the present invention.
In U.S. Pat. No. 6,083,601 issued to Prince, a foam wood extrusion product is disclosed that is formed by the extrusion first of a foam core that then receives a coextruded plastic cladding.